Gypsum wall board



Dec. 26, 1922. 1,999,959.

J. W. EMERSON.

GYPSUM WALL BOARD.

r|LED1uLY2l.1921.

Fig' 4 bw/v W5/Mmm.

l Hoz mg Patente Dec. 26, 1922.

sTATi-:s

PATE

` GYPSUM WALL BoAaD.

Application filed July 21,

To all lwhom it may concern.:

K Be it known that I, JOSEPH W. EMERSON, a citizen of the United States, residing at Salida, county of Chaffee, and State of Colorado, have invented certain new and useful Improvements in Gypsum lV all Board; and I do` declare the following to'be a full, clear, andexact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the characters of ref" erence marked thereon, which form a part of this specification. l f

This invention relates' to an improvement in the design or construction of so-called gypsum wall board. Gypsum wall board as ordinarily made consists essentially of successive layers of cardboard and gypsum plaster, the cardboard being used chiefly as a reinforcing material to give strength to the plaster and for protection in handling.

One of the simplest and commonest forms of gypsum Wallboard consists merely of a layer of gypsum plaster coated on its face and back with cardboard. p

Y. All gypsum wallboards of which I am aware present surfaces of cardboard.` For this reason they are not waterproof and are ruined by Water, since the cardboard, if wet, expands, becomes weak and flabby and tends to detach itself from the gypsum base, and thus to destroy the reinforcing effect.

My invention obviates this difficulty by not using cardboard at the surface, but substituting therefor a meshed material, such as cotton gauze or perforated paper, which, be-

` ing applied While the plaster is in the plastic 40 state, permits a little gypsum to pass through the meshes or openings and thus virtually present a gypsum plaster surface, insteadof a cardboard surface. At the same time the reinforcing effect is at or near the surface where it is most needed and Where it will do the most good.

By this form of construction and with the use of a Waterproof gypsum product which has been subjected to the action of a stearic compound and to a causticcompound4 in the manner described and claimed in my copending application Serial Number 481,083 filed AJune 28, 1921, a waterproofV gypsum board may be made, suitable for exterior as well as interior use.

In order to more clearly describe my in- 192i. serial No. 486,349.

vention I shall refer tothe 'accompanying drawing in which Fig. l represents one form of my wall.

larged scale.

Fig. 3 shows a modified form of wall board with a part broken away to show the reinforcing material, and

Fig. 4 shows a section of Fig. larged scale.

lThe same reference characters represent the same parts throughout the different views.

My improved wall board comprises a body portion l of plaster, which may be a gypsum plaster, a Portland cement product or a magnesite cement product, or in short, any such material which exists in one stage of its formation in the plastic state.

In the process of manufacturing and While the material is lstill in the plastic state, I apply to both sides thereof a meshed material 2 such as cotton gauze, wire cloth, or as 3 on an eny,shown in Figs. 3 and 4, a perforated fabric 3 such as paper. Since the reinforcing material is applied while the materialis still plastic, a little of thel plaster will pass through the meshes or perforations and form a covering of plaster on the outside thereof,

thus producing a plaster surface, which, in case my water repellent gypsum product is used, will be waterproof.

In order to make the plaster slightly re silient and prevent its cracking when nails are driven through it, I mix with the plastic material a small amount of resilient material such cork, sawdust or the like, which is indicated by numeral 4 in the drawing.

The meshed or perforated reinforcing material should be used, not exactly 'at or on the surface but a triiie behind the surface and within the mass of plaster so that the actual surface shall be plaster while the reinforcing loo effect is virtually the same'as if the material 3. A plaster board having a reticulated re' infor-@ing material Within the same and near the surface thereof.

4. A plaster board comprising a Water re- 5 pellent plaster of Paris product having a.

reticulated reinforcing material embedded therein near the surface thereof.

5. plaster board comprising awater repellent plaster of Paris product having sawdust intermixed therewith and meshed reinforcing material embedded therein near the surface thereof.

l 4 JOSEPH 'W EMERSON. 

